Start Discovering Solved Questions and Your Course Assignments
TextBooks Included
Active Tutors
Asked Questions
Answered Questions
benefits of sequential file organisation it is quick and efficient when dealing with huge volumes of data that require being processed periodically
benefits of heap files1 this is a easy file organisation method2 insertion is somehow capable3 good for bulk-loading data
heap files unordered filemostly these files are unordered files it is the easiest and most basic type these files having of randomly ordered records
how are tables stored on diskwe realise that every record of a table can have different amounts of data this is due to in some records some attribute
storage of database on hard disksat this point it is worthwhile to note the difference among the terms file organisation and the access method a file
the issues relating to the design of the physical database filesphysical file is a file as stored on the disk the major issues relating to physical
physical recordsthese are the records that are stored in the secondary storage devices for the database relation physical records are the group of
designing the fields in the data basethe following are the considerations one has to remain in mind while designing the fields in the data base
physical database design issuesthe database design includes the process of logical design with the use of e-r diagram normalisation etc followed by
a suppose we updated the catalog tables in real time that is after every update insert or delete sql statement were executed-rather than only
for this application we will consider ibm db2 catalog data ie metadata for ibms enterprise-class servers running the zos formerly os390 or mvs
objectives after reading this unit you should be able to explain storage of databases on hard disks discuss the execution of various file
file organisation in dbmsintroductiondatabases are used to store information usually the principal operations we have to perform on database are
eliminate columns not dependent on keythe employee relation satisfies -first normal form - as it has no repeating groupssecond normal form - as it do
eliminate redundant datain the database relation above the primary key is made up of the d-id and the emp-id the database-name relies only on the
eliminate repeating groupsthe problem is find out the list of employees who knows db2for this problem we require to perform an awkward scan of the
rules of data normalisation let us now summarise normalisation with the help of various clean rules the following are the necessary rules for the
lack of redundancy we have talked about the problems of repetition of information in a database such repetition should be stay away as much as
dependency preservationit is obvious that the decomposition must be lossless so that we do not lose any information from the relation that is
lossless-join decomposition let us show an intuitive decomposition of a relation we require a better basis for deciding decompositions since
attribute preservationthis is a easy and obvious necessity that includes preserving all the attributes that were there in the relation that is being
desirable properties of decompositiondecomposition is a process of dividing a relation into its projections that will not be disjoint please remind
higher normal forms is there more normal forms beyond bcnf yes though these normal forms are not based on the concept of functional dependence more
boyce-codd normal form bcnfthe relation newstudent enrolmentno sno sname cname cno has every attributes participating in candidate keys as all the
the second normal form 2nfdefinition a relation is in 2nf if it is in 1nf and each non-key attribute is fully dependent on each candidate key of the